DENTIN HYPERSENSITIVITY

DEFINITION

•   the international workshop on dentin hypersensitivity(1983) has proposed the following definition for this condition: “ it is characterised by short,sharp pain arising from exposed dentin in response to stimuli typically thermal,evaporative,tactile,osmotic or chemical and which cannot be ascribed to any other form of dental defect or pathology”

ETIOLOGY

•enamel loss

•occlusal wear

•tooth brush abrasion

•dietary erosion

•abfraction

•parafunctional habits

•cemental loss

•gingival recession

•periodontal disease

•root planing

•periodontal surgery

THEORIES OF DENTIN HYPERSENSITIVITY

1. Direct innervation theory 

 - first theory to be put forward

 - nerve fibers present within dentinal tubules intiate impulses when they are injured

2. Odontoblast deformation theory/transducer theory

 - nerve fibers are present only in the predentin and inner dentinal zones

 - when pain inducing substances like pottasium chloride,acetylcholine are applied to exposed dentin,they fail to elicit painful response.

3. Hydrodynamic theory

 - the most widely accepted mechanism of action of dentin hypersensitivty , the hydrodynamic theory which was proposed by gysi in 1900 and validated by brannstrom in 1996

DIAGNOSIS

1. Complete history	2. Clinical examination	3. Radiographic examination
signs and symptoms	visual assesment	rule out peri apical lesion
intensity	physical assesment
frequency and duration	depth of periodontal pocket depth
dietary changes	percussion testing
	response to cold air

DIFFERENTIAL DIAGNOSIS

1.fractured restorations

2.fractured enamel exposing dentin

3.dental caries

4.post restoration sensitivity

5.cracked tooth syndrome

6.bleaching sensitivity

PREVENTION

1.diet counselling regarding consumption of acidic fruits and beverages

2.correction of brushing technique

3.care during operative procedures

4.care during periodontal procedures

MANAGEMENT

1.Desensitisation by occluding dentinal tubules

a ) formation of smear layer over exposed dentin

b ) use of topical agents to occlude exposed tubules

•  calcium hydroxide paste

•  calcium phosphate paste

•  silver nitrate

•  fluorides

•  fluoride iontophresis

•  potassium nitrate

•  varnishes

•  dentin adhesives

c) placement of restorations

•  glass ionomer cements

•  composite resins 

d) use of lasers  

•  co2 laser

• nd:yag,er:yag laser

• he:ne laser

2. Desensitizing by blocking pulpal sensory nerves

a) potassium nitrate toothpaste

CALCIUM HYDROXIDE

- it increases the remineralisation of the exposed dentin thus reducing dentin permiability

- disadvantage : it causes temporary occlusion of tubules

CALCIUM PHOSPHATE PASTE

• it reduces dentin hypersensitivity by blocking tubules and dentin permeability is reduced

• available product – gc tooth mousse

• it  contains amorphous calcium phosphate and caesin phosphopeptide 

SILVER NITRATE

• it reduses fluid movement by precipitating protein or silver  chloride within the dentinal tubules

• it is not used nowadays as it stains dentin and also damages pulp and gingiva

STRONTIUM CHLORIDE

- The mode of action is linked to their ability to form mineralised deposits within the tubule lumen

and on the surface of the exposed dentine that help prevent transmission of the applied stimulus

FLUORIDES

•agents-sodium fluoride,stannous fluoride or acidulated phosphate fluoride.

•used as mouth rinses,toothpastes or topical application on exposed dentin.

•action is by forming fluorapatite within tubules which block fluid movement within dentin.

FLUORIDE IONTOPHORESIS

• iontophoresis- it is a procedure in which ions of chosen medicament are driven into specific

tissues by means of electric current.

•flouride iontophoresis transfers fluoride ions into dentin for desensitizing it. unit has

•  -positive electrode is placed on patients face or arm

•  -negative electrode is plastic tip placed around the tooth

• 2% sodium fluoride is applied on the  exposed dentin and is transferred deep into the dentin on

  activation of the unit.

•it is reported to provide long-term relief from hypersensitive dentin.

MANAGEMENT

varnishes

• they act by forming a barrier over exposed dentin. This reduces hypersensitivity as it reduces

dentin permeability. they provide only temporary relief.

use of lasers

•they occlude the dentinal tubules by producing local changes around the exposed dentin

•they also produce changes in central pulp neuron.

POTASSIUM NITRATE

• potassium ion may depolarize the nerve and prevent it from repolarizing, thereby, preventing it

  from sending pain signals to the brain.

• potassium ions are thought to diffuse along dentinal tubules and decrease the excitability of

  intradental nerves by altering their membrane potential reducing nerve excitation, and the

associated pain.